As is so often the case for British authors, it has taken a lavish prize from another country for Philip Pullman to be as fully honoured in the UK as he is abroad.

Yesterday Pullman, the author of the Dark Materials trilogy and a holder of the Whitbread book award, was beckoned from his Oxford home to the British Library in London to be formally congratulated for his work by the culture secretary Tessa Jowell, "on behalf of the government".

Then he prepared to fly to Stockholm to collect the cause of these congratulations, the Swedish government's Astrid Lindgren memorial award for children's and youth literature.

The prize, second only to the Nobel prize for literature, is worth £385,000.

Pullman has won it jointly with the Japanese illustrator Ryoji Arai, with whom he will share the prize fund. He will be feted at the Royal Swedish Library and address members of parliament.

The citation for the award calls him "a master storyteller in a number of genres, from historical novels and fantasy to social realism and highly amusing parodies ..."

"Through his strong characters he stands firmly on the side of young people, ruthlessly questioning authority and proclaiming humanism and the power of love whilst maintaining an optimistic belief in the child even in the darkest of situations."

Pullman, 59, once believed it would be hard to find an audience for the trilogy, with its mingled influences from science fiction, William Blake and Tom Paine's Rights of Man. "When people ask me what I meant by this story, or what was the message I was trying to convey in that one, I have to explain that I'm not going to explain.

"Anyway, I'm not in the message business; I'm in the 'Once upon a time' business."